Buried leaching chambers are most commonly used for dispersing wastewaters beneath the surface of ground. Such type chambers may also be used for draining earth or other media. Buried stormwater chambers are used for receiving water, typically from storm, retaining the waters, and then dispersing them, usually by percolation. Commercially popular chambers of such types are made of molded thermoplastic, most commonly by injection molding. Typically they have arch shape cross sections and are coupled end to end at joints to form a string or row of chambers. The ends of the first and last chambers of a string or row have to be closed by end plates or end caps, to keep the surrounding media from entering the chambers.
Water is typically flowed into the chamber at the first end of the string; and thus it is common to have a provision in the end plate for receiving one or more influent flow pipes, which may approach at no particular angle. At times, it is necessary to connect one chamber string to another spaced apart string, where the second string which might run parallel, perpendicular, or at some other angle to the first string. That connection between such chamber strings is frequently made by means of drainpipes penetrating the endplates.
For instance, U.S. Pat. No. 5,839,844 for a leaching chamber endplate and U.S. Pat. No. 5,017,041, for a leaching chamber, both to Nichols et al., show different kinds of flat endplates, which attach to the end of the chamber. As shown by the patents, in the prior art, provisions have been made in endplates, such as a cutout hole, or an embossing for a hole-cut, with the expectation that a pipe will lie substantially parallel to the axis as the chamber. In the prior art, when the drain pipe does not lie close to the extension of the lengthwise axis of the chamber, then plumbing fittings in the drain pipe are used, to make the connection. Particularly in leaching chamber applications, where the wastewater tends to carry solids, it is desirable to minimize any sharp bends in the drain line. It is desirable, for reason of labor and material costs to avoid plumbing work at the job site and to speed installation.